Summary Almost 20% of young people in the US become obese during emerging adulthood (age 18 to 25 years), setting the course for poor health across the life span. At particularly high risk are the 18 million emerging adults with a history of Adverse Childhood Experiences (ACEs), a set of 9 developmentally disruptive childhood experiences such as abuse or parental mental illness. People with ACE histories experience accelerated weight gain in emerging adulthood, leading to an almost 40% increased risk of obesity. Emerging adulthood is a crucial period in which to intervene to reduce obesity risk both because ACE-related obesity appears to emerge at this age and because emerging adults are no longer minors and can be offered intervention independent of parents (who may have contributed to the adversity). Existing interventions can address many of the factors thought to contribute to obesity in those with ACE histories, such as overconsumption of highly palatable ?comfort? food to soothe or numb distress. Thus a promising focus of future research is identifying the optimal combination of these intervention components to reduce ACE-related obesity. However, before we can advance toward such intervention studies, we first need to answer fundamental questions about who should receive interventions and the psychological and behavioral factors that should be addressed. Important questions include: What combinations of ACE exposures are associated with the greatest obesity risk? Do these combinations differ by sociodemographic factors? How are ACEs associated with psychological and behavior factors that offer insight into mechanisms and intervention targets? What types of interventions do those with ACEs and obesity think would be helpful? The proposed study will use an innovative mixed methods approach to answer these questions in emerging adults in 2- and 4-year colleges and universities. We focus on colleges and universities because they serve almost half of all emerging adults, and they offer a feasible and exciting platform for future intervention development. In the quantitative phase of our study, we will leverage and build upon a unique population-based surveillance system of 2- and 4-year college and university students to identify (1) the clusters of ACEs and related adult victimization experiences that are most strongly associated with obesity risk across population groups and (2) associations of these ACE clusters with clusters of psychological and behavior factors that can provide insight into mechanisms and targets for intervention. Second, we will qualitatively explore the links between ACEs and weight behaviors in diverse overweight/obese 2- and 4-year college students with ACE histories. We will conduct in-depth interviews regarding their perception of the reasons for unhealthy weight behaviors, their prior experiences with weight management, and the types of weight management supports they think would be most helpful. This efficient formative study will fill critical gaps in knowledge, providing a foundation for future large-scale work that will optimize and tailor interventions to reduce obesity risk in emerging adults with ACEs